Defect-engineered CoMn layered double hydroxides for enhanced oxygen evolution reaction

Abstract

Synergistically tuning the electronic structure of transition metal hydroxide-based catalysts via multiple defects is an effective approach to enhance their electrocatalyst activity, yet remains challenging due to complexity of conventional synthesis procedure. Herein, a facile, temperature-controlled electrodeposition strategy to introduce abundant oxygen vacancy (O_v), dislocations and wrinkles into CoMn-LDHs subtract. The formation of O_v simultaneously promotes nanosheet wrinkling, which in turn leads to the generation of edge dislocations. These structural defects modulate the local electronic structure of active sites, enhance electrical conductivity, and increase the exposure of active sites, collectively lowering the reaction barrier for the oxygen evolution reaction (OER), as supported by density functional theory calculation. As a result, CoMn-LDH-60/CC delivers outstanding OER performance, featuring a low overpotential of 200 mV at 10 mA·cm⁻² and excellent stability, retaining 97 % of its initial current over 100 h of continuous operation. This study presents a simple and controllable defect-engineering strategy, providing new insights into the rational design of high-performance LDH electrocatalysts.